Display monitor with a common display data channel

ABSTRACT

A display monitor for a common display data channel uses a DDC access switch to separate the common display data channel, so that regardless of whether the display monitor is powered on or off, a personal computer can access the Extended Display Identification Data (EDID) in the EEPROM, and the low-level voltage of an MCU in the display monitor won&#39;t interfere in the access between the personal computer and the EEPROM. When the power of the display monitor is turned on, the DDC access switch closes so that the MCU can access the EDID in the EEPROM.

RELATED APPLICATION

The present application is based on, and claims priority from, TaiwaneseApplication Number 093141120, filed Dec. 29, 2004, the disclosure ofwhich is hereby incorporated by reference herein in its entirety.

REARGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a display monitor, and moreparticularly, to a display monitor with a common display data channel.

2. Description of the Related Art

With technological improvements, image display technologies have becomenecessary components for many electronic products, such as computermonitors, TV screens, cell phone displays, etc. For traditional displaymonitors, only one independent channel exists for accessing EDID(extended display identification data) stored in EEPROMs. However, whena display monitor requires updating, two EEPROMs must be updated, whichwastes time. Therefore, a common display data channel technology hasbeen developed to resolve this problem.

A circuit block drawing of a prior art common display data channel isshown in FIG. 1. A display monitor 20 comprises: an EEPROM 22, a displaymonitor power supply 23, a microprocessor 21, and an internal device 24;the EEPROM 22 is powered by a computer host power supply 11. Both thecomputer host 10 and the microprocessor 21 of the display monitor 20 canaccess the EEPROM 22; consequently, only the EEPROM 22 needs to bewritten to for updating. However, when the display monitor power supply23 of the display monitor 20 is not turned on, the microprocessor 21 ofthe display monitor 20 is turned off too, and so a channel 210 connectedto the microprocessor 21 is at low electrical potential state. Due tothe low electrical potential state of the channel 210, the computer host10 cannot access the EEPROM 22. Moreover, without a power-saving mode,the internal device 24 of the display monitor 20 continuously consumespower.

Therefore, it is desirable to provide a display monitor for a commondisplay data channel to mitigate and/or obviate the aforementionedproblems.

SUMMARY OF THE INVENTION

The present invention provides A display monitor with a common displaydata channel comprises: a first channel connected to a computer host; asecond channel connected to a microprocessor; a display monitor powersupply; a memory device connected to the first channel so the computerhost is capable of accessing the memory device via the first channel; aDDC access switch connected to the first channel, the second channel,and the power supply; wherein when the display monitor power supply isturned on, the first channel and the second channel are provided power;and a microprocessor connected to the second channel and the powersupply; wherein when the display monitor power supply is turned on, themicroprocessor is capable of accessing the memory device via the secondchannel to the first channel by using the DDC access switch.

In the display monitor of the present invention comprises a firstchannel, a second channel, a display monitor power supply, a memorydevice, a microprocessor, and a DDC switch. The first channel isconnected to the memory and a computer host so the computer host canaccess the memory device via the first channel. The second channel isseparately connected to the DDC switch and the microprocessor.Furthermore, the DDC switch is connected to the first channel and thedisplay monitor power supply, when the display monitor power supply isturned off, the DDC switch separates the first channel and the secondchannel to prevent the low electric potential of the second channel fromaffecting transmission of the first channel. When the display monitorpower supply is turned on, the DDC switch conducts the first channel andthe second channel, so the microprocessor can be connected to the firstchannel via the second channel to access the memory device.

The display monitor further comprises an internal device and a powercontrol device connected to the display monitor power supply, the powercontrol device limiting power to the internal device in response toreceiving a saving-energy signal output by the microprocessor.

Furthermore, the first channel and the second channel are display datachannel (DDC).

Other objects, advantages, and novel features of the invention willbecome more apparent from the following detailed description when takenin conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a circuit block drawing of a prior art common display datachannel.

FIG. 2 is a circuit block drawing of a common display data channel of apreferred embodiment according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 2 is a circuit block drawing of a common display data channel of apreferred embodiment according to the present invention. As shown in thedrawing, a display monitor 30 of common display data channel of thepresent invention comprises: a first channel 320, a second channel 310,a display power supply 33, a memory device 38, a microprocessor 31, aDDC switch 37, a composite power supply 36, and an internal device 34.In this embodiment, the memory device 38 is an EEPROM 32.

The first channel 320 is connected to a computer host 10; the EEPROM 32,the DDC switch 37 and the computer host 10 can access EDID (extendeddisplay identification data) from the EEPROM 32 via the first channel320. As long as at least one of either a host power supply 11 or adisplay monitor power supply 33 is turned on, the composite power supply36 can provide power to the EEPROM 32 for operational purposes. Forexample, when the display monitor 30 is not turned on but the computerhost needs to access the EEPROM 32, even though the display monitorpower supply 33 cannot provide power, the composite power supply 36still receives power from the host power device 11 and provides thispower to the EEPROM 32. At the same time, the microprocessor 31 isturned off, and so the second channel 310 is in a low electric potentialstate. However, the DDC switch 37 connected to another end of the secondchannel 310 is also turned on; therefore, the first channel 320 cannotbe connected to the second channel 31, and the low electric potential ofthe second channel 310 does not affect transmission of the first channel320.

When the display monitor 30 is turned on, the display monitor powersupply 33 provides power to the DDC switch 37 and the microprocessor 31,and so the DDC switch 37 can execute a switching process and power thefirst channel 320 and the second channel 310. Subsequently, both thecomputer host 10 and the microprocessor 31 can directly access data fromthe EEPROM 32 to provide common display data channel results and reducedata access failures caused by power shortages of the display monitorpower supply 33.

The composite power supply 36 further comprises two diodes 361, 362separately connected to the host power supply 11 or the display monitorpower supply 33, and the composite power device 36 can provide power tothe EEPROM 32 when either one of the host power supply 11 or the displaymonitor power supply 33 is turned on.

The display monitor 30 further comprises an internal device 34 and apower control device 35. The power control device 35 can be electricallyconnected to the display monitor power device 33, the microprocessor 31,and the internal device 34, and when a user wants to initiate anenergy-save mode, the microprocessor 31 outputs an energy-saving signalto the power control device 35 to stop providing power to the internaldevice 34.

Although the present invention has been explained in relation to itspreferred embodiment, it is to be understood that many other possiblemodifications and variations can be made without departing from thespirit and scope of the invention as hereinafter claimed.

1. A display monitor with a common display data channel comprising: afirst data channel connected to a computer host having a computer hostpower supply; a second data channel connected between the computer hostand a microprocessor; a display monitor power supply; a memory deviceconnected to the first data channel so the computer host is capable ofaccessing the memory device via the first data channel; a compositepower supply connected to the host power supply and the display monitorpower supply for providing power to the memory device; a DDC accessswitch connected to the first data channel, the second data channel, andthe display monitor power supply; wherein when the display monitor powersupply is turned off, the DDC access switch is switched to separate thefirst data channel and the second data channel and the composite powersupply provides power from the host power device to the memory device soas to enable the computer host to access the memory device via the firstdata channel without being affected by low electric potential on thesecond data channel, and when the display monitor power supply is turnedon, the DDC access switch is switched to connect the first data channeland the second data channel; and a microprocessor connected to thesecond data channel and the display monitor power supply; wherein whenthe display monitor power supply is turned on, the composite powersupply provides power from the display monitor power supply to thememory device, so that the microprocessor is capable of accessing thememory device via the second data channel and the first data channelconnected by the DDC access switch.
 2. The display monitor with a commondisplay data channel as claimed in claim 1, wherein the composite powersupply comprises two diodes separately connected to the host powersupply and the display monitor power supply for providing power to thememory device.
 3. The display monitor with a common display data channelas claimed in claim 1, further comprising: an internal device and apower control device connected to the display monitor power supply, thepower control device limiting power to the internal device in responseto receiving a saving-energy signal output by the microprocessor.
 4. Thedisplay monitor with a common display data channel as claimed in claim1, wherein the memory device is an EEPROM stored with extended displayidentification data for the display monitor.